With continuing progress and improvement on electronic technology, compact-sized automobile computers, positioning devices, and electronic devices such as cellular phones and personal digital assistants (PDAs), have continuously progressed. In current market, electronic devices are integrated with multiple functions so as to enhance their competitiveness. Besides functions of photographing, telephoning, and internet surfing, currently, Global Positioning System (GPS), electronic map, and navigation system are also integrated in handheld communication devices, automobile computers, and positioning devices. Users can get their positions by using the GPS anytime and find the best route to the destination through the plan and guidance of navigation systems so as to arrive at the destination fast and safely.
However, GPS is limited to be used for detecting users' positions rather than detecting the others' positions. Thus, if a user wants to guide another person to approach to where he/she is, he/she can lead the person to find the route only in the situation that both ends are equipped with GPS, and the user informs the person about his/her positioning information of current position or uploads the same to device of the person; otherwise, the user has to guide the person by direct oral description.
For example, as a visitor visits a friend without knowing where the friend's home is, the friend has to guide the visitor to his/her home by telephone. However, the visitor has to spend much time on searching the way to the destination because of being not familiar with the surroundings around the friend's home. On the other hand, the friend could fail to guide the visitor properly as he/she does not know the exact position of the visitor.